The solidification microstructure, grain boundary segregation of soluble arsenic, and characteristics of arsenic-rich phases were systematically investigated in Fe–As alloys with different arsenic contents and quenching temperatures. The results show that the solidification microstructures of Fe–0.5wt%As alloys consist of irregular ferrite, while the solidification microstructures of Fe–4wt%As and Fe–10wt%As alloys present the typical dendritic morphology, which becomes finer with increasing arsenic content and quenching temperature. In Fe–0.5wt%As alloys quenched from 1600 and 1200°C, the grain boundary segregation of arsenic is detected by transmission electron microscopy. In Fe–4wt%As and Fe–10wt%As alloys quenched from 1600 and 1420°C, a fully divorced eutectic morphology is observed, and the eutectic Fe2 As phase distributes discontinuously in the interdendritic regions. In contrast, the eutectic morphology of Fe–10wt%As alloy quenched from 1200°C is fibrous and forms a continuous network structure. Furthermore, the area fraction of the eutectic Fe2 As phase in Fe–4wt%As and Fe–10wt%As alloys increases with increasing arsenic content and decreasing quenching temperature. The solidification microstructure, grain boundary segregation of soluble arsenic, and characteristics of arsenic-rich phases were systematically investigated in Fe-As alloys with different arsenic contents and quenching temperatures. The results show that the solidification microstructures of Fe-0.5 wt% of irregular ferrite, while the solidification microstructures of Fe-4 wt% As and Fe-10 wt% As alloys present the typical dendritic morphology, which becomes finer with increasing arsenic content and quenching temperature. 1200 ° C, the grain boundary segregation of arsenic was detected by transmission electron microscopy. In Fe-4wt% As and Fe-10wt% As alloys quenched from 1600 and 1420 ° C, a fully divorced eutectic morphology was observed, and the eutectic Fe2 In contrast, the eutectic morphology of Fe-10 wt% As alloy quenched from 1200 ° C is fibrous and Forms a continuous network structure. Further, the area fraction of the eutectic Fe2 As phase in Fe-4 wt% As and Fe-10 wt% As alloys increases with increasing arsenic content and decreasing quenching temperature.